Search

Bio-based composite films have been widely studied as potential substitutes for conventional plastics in food packaging. The aim of this study was to develop multifunctional composite films by introducing cellulose nanofibers (CNF) and lignin into starch-based films. Instead of costly and complicated chemical modification or covalent coupling, this study optimized the performance of the composite films by simply tuning the formulation. We found that starch films were mechanically reinforced by CNF, with lignin dispersing as nanoparticles embedded in the matrix. The newly built-up hydrogen bonding between these three components improves the integration of the films, while the introduction of CNF and lignin improved the thermal stability of the starch-based films. Lignin, as a functional additive, improved hydrophobicity and blocked UV transmission. The inherent barrier property of CNF and the dense starch matrix provided the composite films with good gas barrier properties. The prepared flexible films were optically transparent, and exhibited UV blocking ability, good oxygen-barrier properties, high hydrophobicity, appreciable mechanical strength and good thermal stability. These characteristics indicate potential utilization as a green alternative to synthetic plastics especially for food packaging applications.

Extracellular matrices play important, but poorly investigated, roles in morphogenesis. Extracellular cellulose is central to regulation of pattern formation in plants, but among metazoans only tunicates are capable of cellulose biosynthesis. Cellulose synthase (CesA) gene products are present in filter-feeding structures of all tunicates and also regulate metamorphosis in the ascidian Ciona. Ciona CesA is proposed to have been acquired by lateral gene transfer from a prokaryote. We identified two CesA genes in the sister-class larvacean Oikopleura dioica. Each has a mosaic structure of a glycoslyltransferase 2 domain upstream of a glycosyl hydrolase family 6 cellulase-like domain, a signature thus far unique to tunicates. Spatial-temporal expression analysis revealed that Od-CesA1 produces long cellulose fibrils along the larval tail, whereas Od-CesA2 is responsible for the cellulose scaffold of the post-metamorphic filter-feeding house. Knockdown of Od-CesA1 inhibited cellulose production in the extracellular matrix of the larval tail. Notochord cells either failed to align or were misaligned, the tail did not elongate properly and tailbud embryos also exhibited a failure to hatch. Knockdown of Od-CesA2 did not elicit any of these phenotypes and instead caused a mild delay in pre-house formation. Phylogenetic analyses including Od-CesAs indicate that a single lateral gene transfer event from a prokaryote at the base of the lineage conferred biosynthetic capacity in all tunicates. Ascidians possess one CesA gene, whereas duplicated larvacean genes have evolved distinct temporal and functional specializations. Extracellular cellulose microfibrils produced by the premetamorphic Od-CesA1 duplicate have a role in notochord and tail morphogenesis. Norwegian Research CouncilResearch Council of NorwayEuropean Commission [17541/S10] We thank the staff from Appendic Park for supplying animals, and Daniel Chourrout, Sars and Genoscope, France for the development of Oikopleura genomic resources. This work was supported by grant 17541/S10 NFR-FUGE from the Norwegian Research Council (E. M. T.).

Atmospheric CO2 is projected to double by 2100, resulting in elevated temperatures and ocean acidification (OA). A lack of multifactorial studies means limited knowledge on the combined effects of these pressures on ecosystem structure and function. Laboratory data suggest that increasing temperature and decreasing pH, mimicking expected changes, may differentially impact major zooplankton groups. Filter-feeding appendicularians ingest smaller food than copepods, by-passing the microbial loop, and directly transferring bacteria and nanoplankton to higher trophic levels. They are also vectors of global vertical carbon flux through trapping of prey in their frequently discarded houses. We obtained mono-factorial laboratory data suggesting that OA positively affects fitness parameters in Oikopleura through decreased generation time, faster growth, increased survival and egg Atmospheric CO2 is projected to double by 2100, resulting in elevated temperatures and ocean acidification (OA). A lack of multifactorial studies means limited knowledge on the combined effects of these pressures on ecosystem structure and function. Laboratory data suggest that increasing temperature and decreasing pH, mimicking expected changes, may differentially impact major zooplankton groups. Filter-feeding appendicularians ingest smaller food than copepods, by-passing the microbial loop, and directly transferring bacteria and nanoplankton to higher trophic levels. They are also vectors of global vertical carbon flux through trapping of prey in their frequently discarded houses. We obtained mono-factorial laboratory data suggesting that OA positively affects fitness parameters in Oikopleura through decreased generation time, faster growth, increased survival and egg production. To assess these effects in more complex natural ecosystems we have conducted a pilot mesocosm experiment use a 2x2x3 factorial design to assess effects of temperature, pCO2 and phytoplankton regimes on zooplankton population dynamics. Data will be presented showing the extent to which OA and temperature modulation of Oikopleura fitness parameters noted in the laboratory are also observed at the mesocosm scale

The monitoring of the reproduction of Crassostrea gigas, and more occasionally that of the mussel Mytilus edulis, is carried out in the Marennes-Oléron Basin, each year, from June through to September. This report presents the main results obtained in 1997, 1998, 1999, 2000 and compares them. It also recalls the techniques used and provides, in appendix, some bibliographic information on larval development., Le suivi de la reproduction de l'huître creuse Crassostrea gigas, et plus ponctuellement celui de la moule Mytilus edulis, s'effectuent dans le Bassin de Marennes-Oléron, chaque année, de juin à septembre. Ce rapport donne les principaux résultats obtenus en 1997, 1998, 1999,2000 et compare les résultats d'une année à l'autre. Il rappelle également les techniques utilisées, et fournit en annexe des informations bibliographiques sur le développement larvaire.

Monitoring of reproduction in the oyster Crassostrea gigas, and more particularly in the mussel Mytilis edulis were conducted, in the Marennes-Oléron Bay each year, from June to September. This report gives the main results obtained in 1997, 1998, 1999,2000 and compares the results between years. It also summarises the fishing techniques used and gives information on larval development in the annexes. NOT CONTROLLED OCR, Le suivi de la reproduction de l'huître creuse Crassostrea gigas, et plus ponctuellement celui de la moule Mytilus edulis, s'effectuent dans le Bassin de Marennes-Oléron, chaque année, de juin à septembre. Ce rapport donne les principaux résultats obtenus en 1997, 1998, 1999,2000 et compare les résultats d'une année à l'autre. Il rappelle également les techniques utilisées, et fournit en annexe des informations bibliographiques sur le développement larvaire. OCR NON CONTRÔLE

The microbiological classification of the Marennes-Oléron shellfish farming area (according to Council Directive 91/492/EEC) let appear sorne periodically polluted spots. A research of the potentiel sources has been conducted around these spots. Twelve points were sampled during a year with faecal coliforms and streptococcus contamination level in water (and shellfich when possible). Several microbiological pollution sources were found, in the Seudre estuary (umstream) and in Oléron island : lack of, or ineffective sewage systems, cattle farming without convenient manure treatrrtent, and so on .. Recommendations are given to improve this situation., La classification sanitaire des zones de production du bassin ostréicole de Marennes Oléron a fait apparaître des zones B (soumises à des pollutions bactériologiques périodiques). Une recherche des sources potentielles de contamination bactériologique a été entreprise sur la périphérie du bassin, dans des zones où l'on pouvait observer des dysfonctionnements de l'assainissement urbain ou rural. Douze points ont été suivis pendant un an par recherche des germes fécaux dans l'eau, voire dans des coquillages immergés sur le site. Plusieurs foyers de pollution en amont de Seudre sont ainsi mis en évidence, de même que sur la périphérie de Saint-Pierre d'Oléron (aboutissant au chenal ostréicole de la Perrotine) : assainissement inexistant, défauts de raccordement, élevages agricoles sans installation de recueil des eaux usées, etc ... Des recommandations sont faites pour remédier à ces situations, nuisibles à la qualité sanitaire des coquillages.

The Marennes-Oléron is a well known cupped oyster (Crassostrea gigas) and mussel (Mytilus edulis) reproduction area. Every year, a monitoring of the reproduction of these two species is carried out on behalf of the Regional Shellfish Culture Section of Marennes-Oléron. This monitoring aims to determine the periods of larval emission in order to let the professionals know about the best collection times This study presents the main results obtained in 1999 and compares them with those obtained in 1997 and 1998. The year 1999 showed good results as far as larval emission and development are concerned in both oysters and mussels. The comparison of the three consecutive years shows the disparity of larval evolutions., Le bassin de Marennes-Oléron est une zone reconnue de reproduction des huîtres creuses (Crassostrea gigas) et des moules (Mytilus edulis). Comme chaque année, un suivi de la reproduction de ces deux espèces est effectué à la demande de la Section Régionale Conchylicole de Marennes-Oléron. Ce suivi a pour objet de déterminer les périodes d'émissions larvaires afin d'informer les professionnels des époques les plus propices au captage. La présente étude expose d'une part les principaux résultats obtenus pour l'année 1999 et d'autre part une comparaison de ces derniers à ceux des années 1997 et 1998. L'année 1999 a montré de très bon résultats en matière d'émission et de développement larvaire aussi bien pour les huîtres que pour les moules. La comparaison des trois années met en évidence la disparité des évolutions larvaires.

Trois études de zones ont été conduites en 1997/1998 dans le bassin de Marennes-Oléron (Charente-Maritime). Deux concernaient la contamination des coquillages fouisseurs de la Seudre et du banc de Ronce-Perquis. La troisième concernait la contamination des coquillages filtreurs des bouchots à moules des Saumonards (Ile d'Oléron). Ces études avaient pour objet d'évaluer les niveaux de contamination microbiologique et chimique de ces zones de production de coquillages afin que l'Administration puisse en effectuer le classement sanitaire conformément à l'arrêté du 21 juillet 1995. La Seudre, à l'aval de la rivière, a montré, pour les fouisseurs, une qualité microbiologique de catégorie B et une qualité microbiologique de catégorie C pour la partie amont. De son côté, le Banc de Ronce-Perquis a présenté, pour les fouisseurs, une qualité microbiologique de catégorie B. Enfin, la catégorie microbiologique des moules des bouchots des Saumonards est de type A. Le suivi du mercure total, du cadmium et du plomb dans la chair des coquillages a mis en évidence des teneurs inférieures aux valeurs seuil.

Le suivi de la reproduction des huîtres s'est déroulé du 22 juin au 3 septembre 1998. Six points du bassin de Marennes-Oléron sont à nouveau concernés : En Charente: La Mouclière et Les Palles. Au centre du Bassin: Les Doux et Mérignac; En Seudre: Coux et les Faulx. Cette opération est contractualisée avec la Section Régionale de Marennes-Oléron.